/*
 * Tencent is pleased to support the open source community by making TBase available.  
 * 
 * Copyright (C) 2019 Tencent.  All rights reserved.
 * 
 * TBase is licensed under the BSD 3-Clause License, except for the third-party component listed below. 
 * 
 * A copy of the BSD 3-Clause License is included in this file.
 * 
 * Other dependencies and licenses:
 * 
 * Open Source Software Licensed Under the PostgreSQL License: 
 * --------------------------------------------------------------------
 * 1. Postgres-XL XL9_5_STABLE
 * Portions Copyright (c) 2015-2016, 2ndQuadrant Ltd
 * Portions Copyright (c) 2012-2015, TransLattice, Inc.
 * Portions Copyright (c) 2010-2017, Postgres-XC Development Group
 * Portions Copyright (c) 1996-2015, The PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, The Regents of the University of California
 * 
 * Terms of the PostgreSQL License: 
 * --------------------------------------------------------------------
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without a written agreement
 * is hereby granted, provided that the above copyright notice and this
 * paragraph and the following two paragraphs appear in all copies.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
 * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 * 
 * 
 * Terms of the BSD 3-Clause License:
 * --------------------------------------------------------------------
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation 
 * and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of Tencent nor the names of its contributors may be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS 
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 
 * DAMAGE.
 * 
 */
/*
 * pgp-info.c
 *      Provide info about PGP data.
 *
 * Copyright (c) 2005 Marko Kreen
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * contrib/pgcrypto/pgp-info.c
 */
#include "postgres.h"

#include "contrib/pgcrypto/px.h"
#include "contrib/pgcrypto/mbuf.h"
#include "contrib/pgcrypto/pgp.h"

static int
read_pubkey_keyid(PullFilter *pkt, uint8 *keyid_buf)
{
    int            res;
    PGP_PubKey *pk = NULL;

    res = _pgp_read_public_key(pkt, &pk);
    if (res < 0)
        goto err;

    /* skip secret key part, if it exists */
    res = pgp_skip_packet(pkt);
    if (res < 0)
        goto err;

    /* is it encryption key */
    switch (pk->algo)
    {
        case PGP_PUB_ELG_ENCRYPT:
        case PGP_PUB_RSA_ENCRYPT:
        case PGP_PUB_RSA_ENCRYPT_SIGN:
            memcpy(keyid_buf, pk->key_id, 8);
            res = 1;
            break;
        default:
            res = 0;
    }

err:
    pgp_key_free(pk);
    return res;
}

static int
read_pubenc_keyid(PullFilter *pkt, uint8 *keyid_buf)
{
    uint8        ver;
    int            res;

    GETBYTE(pkt, ver);
    if (ver != 3)
        return -1;

    res = pullf_read_fixed(pkt, 8, keyid_buf);
    if (res < 0)
        return res;

    return pgp_skip_packet(pkt);
}

static const char hextbl[] = "0123456789ABCDEF";

static int
print_key(uint8 *keyid, char *dst)
{
    int            i;
    unsigned    c;

    for (i = 0; i < 8; i++)
    {
        c = keyid[i];
        *dst++ = hextbl[(c >> 4) & 0x0F];
        *dst++ = hextbl[c & 0x0F];
    }
    *dst = 0;
    return 8 * 2;
}

static const uint8 any_key[] =
{0, 0, 0, 0, 0, 0, 0, 0};

/*
 * dst should have room for 17 bytes
 */
int
pgp_get_keyid(MBuf *pgp_data, char *dst)
{
    int            res;
    PullFilter *src;
    PullFilter *pkt = NULL;
    int            len;
    uint8        tag;
    int            got_pub_key = 0,
                got_symenc_key = 0,
                got_pubenc_key = 0;
    int            got_data = 0;
    uint8        keyid_buf[8];
    int            got_main_key = 0;


    res = pullf_create_mbuf_reader(&src, pgp_data);
    if (res < 0)
        return res;

    while (1)
    {
        res = pgp_parse_pkt_hdr(src, &tag, &len, 0);
        if (res <= 0)
            break;
        res = pgp_create_pkt_reader(&pkt, src, len, res, NULL);
        if (res < 0)
            break;

        switch (tag)
        {
            case PGP_PKT_SECRET_KEY:
            case PGP_PKT_PUBLIC_KEY:
                /* main key is for signing, so ignore it */
                if (!got_main_key)
                {
                    got_main_key = 1;
                    res = pgp_skip_packet(pkt);
                }
                else
                    res = PXE_PGP_MULTIPLE_KEYS;
                break;
            case PGP_PKT_SECRET_SUBKEY:
            case PGP_PKT_PUBLIC_SUBKEY:
                res = read_pubkey_keyid(pkt, keyid_buf);
                if (res < 0)
                    break;
                if (res > 0)
                    got_pub_key++;
                break;
            case PGP_PKT_PUBENCRYPTED_SESSKEY:
                got_pubenc_key++;
                res = read_pubenc_keyid(pkt, keyid_buf);
                break;
            case PGP_PKT_SYMENCRYPTED_DATA:
            case PGP_PKT_SYMENCRYPTED_DATA_MDC:
                /* don't skip it, just stop */
                got_data = 1;
                break;
            case PGP_PKT_SYMENCRYPTED_SESSKEY:
                got_symenc_key++;
                /* fallthru */
            case PGP_PKT_SIGNATURE:
            case PGP_PKT_MARKER:
            case PGP_PKT_TRUST:
            case PGP_PKT_USER_ID:
            case PGP_PKT_USER_ATTR:
            case PGP_PKT_PRIV_61:
                res = pgp_skip_packet(pkt);
                break;
            default:
                res = PXE_PGP_CORRUPT_DATA;
        }

        if (pkt)
            pullf_free(pkt);
        pkt = NULL;

        if (res < 0 || got_data)
            break;
    }

    pullf_free(src);
    if (pkt)
        pullf_free(pkt);

    if (res < 0)
        return res;

    /* now check sanity */
    if (got_pub_key && got_pubenc_key)
        res = PXE_PGP_CORRUPT_DATA;

    if (got_pub_key > 1)
        res = PXE_PGP_MULTIPLE_KEYS;

    if (got_pubenc_key > 1)
        res = PXE_PGP_MULTIPLE_KEYS;

    /*
     * if still ok, look what we got
     */
    if (res >= 0)
    {
        if (got_pubenc_key || got_pub_key)
        {
            if (memcmp(keyid_buf, any_key, 8) == 0)
            {
                memcpy(dst, "ANYKEY", 7);
                res = 6;
            }
            else
                res = print_key(keyid_buf, dst);
        }
        else if (got_symenc_key)
        {
            memcpy(dst, "SYMKEY", 7);
            res = 6;
        }
        else
            res = PXE_PGP_NO_USABLE_KEY;
    }

    return res;
}
